Ancient Monuments

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Coastal fish weir at the northern end of The Nass

A Scheduled Monument in West Mersea, Essex

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Latitude: 51.7622 / 51°45'44"N

Longitude: 0.8963 / 0°53'46"E

OS Eastings: 599966.0982

OS Northings: 211030.1374

OS Grid: TL999110

Mapcode National: GBR SPP.KDJ

Mapcode Global: VHKGK.HY6Y

Entry Name: Coastal fish weir at the northern end of The Nass

Scheduled Date: 6 October 2000

Source: Historic England

Source ID: 1019581

English Heritage Legacy ID: 32404

County: Essex

Civil Parish: West Mersea

Built-Up Area: West Mersea

Traditional County: Essex

Lieutenancy Area (Ceremonial County): Essex

Church of England Parish: Tollesbury St Mary the Virgin

Church of England Diocese: Chelmsford


The monument includes a substantial coastal fish weir located at the mouth of
Tollesbury Fleet, some 600m south east of Old Hall Marshes.
The timber weir was first recorded at ground level by Mr Ron Hall, a local
amateur archaeologist, in January 1993, and was subsequently photographed from
the air by Steve Wallis of the Archaeological Advisory Group of Essex County
It is a V-shaped timber weir with walls measuring 120m (north east to south
west) and 130m (north-south) converging to the north east, where a long narrow
structure also of upright timbers forms an elongated trap area. Evidence for
various phases of construction and repair can be discerned; the southernmost
wall appears to have at least two phases of rebuilding at slightly different
angles. The walls are constructed using upright timbers infilled with panels
of hurdling; the latter, in addition to forming the infill for the walls of
the weir, may have formed a walkway along the walls in order to allow access
to the fish trap areas of the structure. Some of the large timbers from the
site have features such as mortice holes and tenons. Samples of the timbers
were taken for radiocarbon analysis and gave a date range of AD 664-882.
As with several other timber fish weirs constructed in the estuary in the
Anglo-Saxon or medieval period, it was clearly designed to exploit the action
of the tides in the inter-tidal zone of the day.

The site of the monument is shown on the attached map extract.
It includes a 10 metre boundary around the archaeological features,
considered to be essential for the monument's support and preservation.

Source: Historic England

Reasons for Scheduling

Coastal fish weirs are artificial barriers created within the inter-tidal
zone, using stone walls, wattle or timber fencing to channel fish into traps.
The most common form of weir (a term derived from `were' - an Anglo-Saxon word
meaning fish trap) is a simple `V'-shaped arrangement of walls, frequently
100m or more in length. Baskets or nets would be placed at the point of the
`V' which would normally be orientated seaward so as to draw in the fish with
the receding tide. Weirs may also be rectangular or more linear in appearance
with traps located either in corners or set within spurs attached to the main
walls. Placed in gently shelving coastal or estuarine locations, the weirs
would become sufficiently exposed at low water for the fish to be collected
and, in some instances, for initial processing (gutting, filleting) to take
place on site.
Stationary fish traps are known to have been used since the Mesolithic period,
although the earliest examples to leave strong visible traces around the
coastline belong to a tradition dating from the early medieval or Anglo-Saxon
period. Documentary evidence from the 10th century onwards suggests that fish
weirs were largely the preserve of the upper echelons of medieval society,
maintained either by larger manors or by religious houses. In addition to the
obvious advantage of a constant food supply, the produce from the fish weirs
provided economic benefit, indicated social status and could aid compliance
with the religious dietary strictures of the period. Large fish weirs were
still used in the Severn Estuary until the early 20th century, and their
small-scale use persists here and in other parts of the British Isles to this
day. In general, however, the practice reached its peak between the 12th and
14th centuries, hereafter declining in the face of growing commercial sea
fishing. The remains of about 500 fish weirs are estimated to survive around
England's coast. Those of medieval or earlier date which demonstrate a high
degree of preservation, and particularly those which form groups or have
demonstrable links with manorial or ecclesiastical estates, will normally be
considered to be of national importance and worthy of protection.

Inspection at ground level has shown the weir at the northern end of The Nass
to be in a good state of preservation; the upright timbers survive well and
there are several areas of hurdling still extant. The timber post alignments
show the overall layout of the weir and provide clear evidence for its
original design and the manner in which it operated.
Radiocarbon dating gives a date range for the monument of AD 664-882,
providing a direct parallel with the coastal fish weir at Sales Point, which
has also been radiocarbon dated to AD 656-957,the Middle Saxon period.
Documentary evidence concurs with the radiocarbon dating: the Domesday Book
lists a fishery at Tollesbury, almost certainly referring to the weir at The

Source: Historic England


Books and journals
Rumble, A (ed.), Domesday Book, (1983)
Strachan, D, C14 dating of some inter-tidal fish-weirs in Essex, (1997)
Eleven colour prints from slides, Hall, R, Unreferenced - ESMR number 9974 only, (1993)
Fourteen black-and-white prints, Pearce, B, Unreferenced - ESMR number 9974 only, (1993)
One black-and-white print, Rogers, P, SWBW14-3, (1993)
One colour print, Austin, L, BESP Film 3 Frame 24, (1993)
Strachan, D, TL91SE 1:10000, (1996)
Three black-and-white prints, Strachan, D, BW/1994/1/9,, (1994)
Two colour prints, Strachan, D, CP/96/41/1, (1996)
Two colour prints, Strachan, D, CP/97/5/11, (1997)
Two colour prints; three b/w prints, Bruce, K, KBC 8,9; KBBW 27,28,29, (1993)

Source: Historic England

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